|Publication number||US7551177 B2|
|Application number||US 11/216,690|
|Publication date||Jun 23, 2009|
|Filing date||Aug 31, 2005|
|Priority date||Aug 31, 2005|
|Also published as||CN101341508A, EP1932111A1, US20070046682, WO2007026244A1|
|Publication number||11216690, 216690, US 7551177 B2, US 7551177B2, US-B2-7551177, US7551177 B2, US7551177B2|
|Inventors||Chris Brennan, John Isidoro, Anthony DeLaurier|
|Original Assignee||Ati Technologies, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (10), Non-Patent Citations (1), Classifications (19), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present disclosure relates to methods and apparatus for retrieving and combining graphics information and, more particularly, retrieving sampled channel data and combining the sample channel data into a single vector.
In image processing circuits, such as a graphics processing unit, logic and algorithms are typically included to perform texturing of image data to be displayed. More specifically, image filtering, which is performed in the texturing process such as in a texture pipeline, is performed following many different techniques. As examples, known filtering techniques include percentage closer filtering or any similar high order filtering that composes multiple samples of image data together. For example, in bilinear filtering, conventional texture fetching pipelines sample up to four neighboring points for filtering. These samples are then blended together by using weights calculated from the sub-texel position of the sample point within a particular texel box, which is one of the four samples. Further, each of the samples comprises a vector having up to four channels designated typically as R, G, B, and A where R stands for red, G stands for green, B stands for blue, and A denotes alpha, which is typically a transparency value. The result of the filtering is a single vector having up to four channels where the single vector is a blend of the original four vectors (i.e., samples).
There are instances where values of the four samples may be desirable to be used without bilinear filtering in order that custom operations may be performed within a shader in the texture pipeline. Example instances include Percentage Closer Filtering, which compares one channel of the sample with a provided distance and replaces it with a 0.0 or 1.0 value before performing the filtering, and higher order filters, which may require multiple fetches and changing of the blend weights before filtering. Conventional algorithms and accompanying logic typically obtain such values by performing four separate fetches for each of the samples being filtered. Four fetches comes from the fact that there are four components in a vector. There are four neighbors in a two dimensional surface. Filter algorithms usually use four samples, but many use a larger neighborhood, and in those cases several fetch four operations can be used to create the filter at four times the fetch speed compared to doing them individually. In any event, by performing four fetches per vector, the time needed to retrieve that sample data increased.
The present disclosure discusses methods and apparatus for accomplishing the fetching or sampling of channels of pixels, such as but not limited to neighboring pixels or texels, in a simultaneous operation in order to achieve optimization of the performance of a pixel or texture pipeline. In particular, logic is disclosed including selector logic configured to retrieve data including a plurality of channels from each of a plurality of pixels, such as adjacent pixels or texels, non-neighboring pixels or texels or any suitable pixels or texels and is operable to select one channel from the plurality of channels of the data from each of the pixels or texels. The logic also includes combination logic configured to combine two or more of the selected channels into a single vector, such as an RGBA vector representing the color.
The present disclosure also discloses a method for combining pixel or texel information including simultaneously sampling channel data from two or more pixels. The method further includes selecting a channel for each of the sample channel data from the two or more pixels or texels and then combining the plurality of selected channels into a single vector. By simultaneously sampling the data or fetching the data, the timing of filtering is optimized over the conventional methods and apparatus requiring four separate fetches.
It is noted that each of the texels 204, 206, 208, and 210 include the four RGBA channels. A selector logic 214, corresponding to selector logic 114 in
The selected channel, which is red in this example, is then output by the selector logic 214 as components of an RGBA vector as illustrated by lines 224, 226, 228 and 230. In other words, although the selection logic selects only red channels from each of the texels 204, 206, 208 and 210, the output of the selector logic represents the red channel of top left pixel 204 as a red (R) channel 224, the red channel of top right texel 206 as a green (G) channel 226, the red channel of bottom left texel 208 as blue (B) channel 230, and the red channel of texel 210 as the alpha (A) channel 228. This information is then delivered to combination logic 232, which corresponds to combination logic 116 in
As disclosed, the apparatus and methods discussed achieve optimization of the performance of a pixel pipeline or texture pipeline by fetching or sampling of channels of pixels such as but not limited to neighboring pixels (or texels) in a simultaneous operation and immediately combing the sampled channels into a vector that is subsequently output to a shader, for example. Thus, the presently disclosed apparatus and methods avoid having to sample each of the four channels of a pixel or texel one at a time before outputting a vector, thereby reducing the time required for performing filtering, such as percentage closer filtering, for example.
The above detailed description of the present examples has been presented for the purposes of illustration and description only and not by limitation. It is therefore contemplated that the present application cover any additional modifications, variations, or equivalents but fall within the spirit and scope of the basic underlying principles disclosed above and the appended claims.
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|U.S. Classification||345/582, 345/423, 382/300, 382/253, 345/606, 345/561, 345/505, 382/260, 382/305|
|International Classification||G06T15/04, G06K9/00, G09G5/37, G06K9/40, G06F15/80, G09G5/00, G06K9/60|
|Cooperative Classification||G06T2200/28, G06T15/04|
|Nov 17, 2005||AS||Assignment|
Owner name: ATI TECHNOLOGIES INC., CANADA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BRENNAN, CHRIS;ISIDORO, JOHN;DELAURIER, ANTHONY;REEL/FRAME:016794/0693;SIGNING DATES FROM 20051028 TO 20051031
|May 12, 2011||AS||Assignment|
Effective date: 20061025
Owner name: ATI TECHNOLOGIES ULC, CANADA
Free format text: CHANGE OF NAME;ASSIGNOR:ATI TECHNOLOGIES INC.;REEL/FRAME:026270/0027
|Oct 4, 2012||FPAY||Fee payment|
Year of fee payment: 4